Australian father Harry Speath has left New Zealand without finding his two missing children.
Mr Speath hasn't seen eight-year-old Serena and seven-year-old Thomas since December 2014. He believed there was a chance his ex-wife Jane Adare was hiding with the children in Christchurch.
He called on the help of child recovery specialist Col Chapman, who helped reunite six-year-old Que with her mother after her father Alan Langdon sailed away with her to Australia.
Mr Chapman believed there was a chance New Zealand could end the two-and-a-half-year search.
"We've had at least eight people claim they have seen her in the Christchurch area and another couple say she looks familiar from the South Island," he says.
Mr Speath flew in to the city on Friday afternoon to speak with police and seek help from the public during the four day visit.
"Unfortunately Harry has had to head back to Australia today to recommence the search here. Harry isn't giving up," Mr Chapman says.
When Mr Speath arrived at Christchurch International airport on Friday it had been an emotionally draining search.
"It's been fairly horrendous really. I can't tell you how distraught I was in the beginning," Mr Speath said
The couple had a week-about custody agreement with his wife who picked the children up from his house in December 2014 and drove off without any trace or contact since.
The Australian Federal Police has issued a warrant for her arrest and Interpol has been alerted around the world.